DEVELOPMENT OF PARASITE OF ORIENTAL SORE. 749 
shown as a well-defined margin. The length of the body is 
about one-third that of a red blood-cell; the parasites are 
therefore a little smaller than those described by James (2), 
but on the whole the descriptions of Wright (3) and James 
are applicable to the bodies seen in my specimens. 
‘he micronucleus seems to be more often dot-shaped 
than rod-shaped, and separation of the dot-shaped micro- 
nucleus from the macronucleus can be seen in different 
stages (figs. 2 and 3). From the study of the smears I 
am inclined to think that the youngest stage of the para- 
site is the torpedo-shaped form (fig. 2, a-c) with a single 
nucleus [or with the two nuclei closely apposed], and that 
the separation of the two nuclei in these spore-lke forms 
comes about after the parasite has entered the macrophage ; 
in other words, that the parasite undergoes development in 
the macrophage, and that the free parasites showing the 
typical characters of the two nuclei (fig. 2, d, e, fig. 3, d, f) 
are those which have been liberated trom a macrophage, 
either by its disintegration or by ejection from it. 
The parasites contained in macrophages are seen to be 
lodged inside a vacuole or clear space (fig. 1) ; possibly some 
sort of secretion is thrown out round the parasite by the 
macrophage. 
The parasites multiply by fission (fig. 3, e, g), as described 
by previous observers. Heart-shaped nuclei are seen in some 
ot the parasites in the smears. 
(3) ‘he phases of the development of the para- 
site in cultures.—After twenty-four hours the cultures, 
examined in the fresh condition or in stained smears, showed 
no very obvious increase in the numbers of the parasites, but 
a sparing distribution in groups of four or eight. The body 
of the parasite 1s increased to double its former size, but 
shows no other difference, except, perhaps, rather better 
staining of the body-protoplasm. 
After forty-eight hours the parasites have grown and 
multiphed enormously, and are found in masses (fig. 4), 
visible under the low power. Isolated individuals are also to 
